The invention relates to an air impingement system for heating and drying the web travelling around the air impingement roll in the drying section of a paper machine or the like.
A solution of using an air impingement system in the drying section of a paper machine or the like has been presented in U.S. Pat. No. 6,138,380, in which an air impingement roll, the diameter of which is considerably larger than the diameter of a normal drying cylinder, is used as an air impingement roll. Due to its large size, this kind of an air impingement roll does not normally even fit underneath a paper machine in the basement, when the paper machine is being modernised. The structure is also sensitive to problems caused by shredded paper. Drying can also be made more efficient with the method disclosed in U.S. Pat. No. 6,148,538, although the efficiency of the condensation means for removing moisture is not necessarily very high in structures of this kind.